The invention relates to a display device comprising a plurality of electroluminescent diodes and means for causing one or more of the diodes to luminesce in dependence upon a voltage to be supplied between two connection points.
Electroluminescent (EL) or light-emitting display devices of this type may be used in, for example displays and level indicators for checking battery voltages, and as voltage meters in, for example shavers, portable telephones, for output power display in audio applications, etc.
Such level indicators are generally known and comprise a plurality of juxtaposed light-emitting diodes (LEDs) with the voltage supplied to the above-mentioned connection points determining the number of LEDs which luminesces. Such a circuit comprises a plurality of LEDs, each in its own housing, which are arranged on a printed circuit board so as to work together functionally. The supplied voltage is converted via an A/D converter into a digital value; the number of diodes to be energized is determined via a second IC (or via integration in the A/D converter).
The costs of placing and mounting said components are generally high. Moreover, the printed circuit requires extra space and covers a considerable part of the volume, particularly in the case of portables.